elf_module.c

这是一个开放源代码的与WINNT/WIN2K/WIN2003兼容的操作系统

/*
 * File elf.c - processing of ELF files
 *
 * Copyright (C) 1996, Eric Youngdale.
 *		 1999-2004 Eric Pouech
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "config.h"

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <fcntl.h>
#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#ifndef PATH_MAX
#define PATH_MAX MAX_PATH
#endif

#include "dbghelp_private.h"

#if defined(__svr4__) || defined(__sun)
#define __ELF__
#endif

#ifdef HAVE_ELF_H
# include <elf.h>
#endif
#ifdef HAVE_SYS_ELF32_H
# include <sys/elf32.h>
#endif
#ifdef HAVE_SYS_EXEC_ELF_H
# include <sys/exec_elf.h>
#endif
#if !defined(DT_NUM)
# if defined(DT_COUNT)
#  define DT_NUM DT_COUNT
# else
/* this seems to be a satisfactory value on Solaris, which doesn't support this AFAICT */
#  define DT_NUM 24
# endif
#endif
#ifdef HAVE_LINK_H
# include <link.h>
#endif
#ifdef HAVE_SYS_LINK_H
# include <sys/link.h>
#endif

#include "wine/debug.h"

WINE_DEFAULT_DEBUG_CHANNEL(dbghelp);

struct elf_module_info
{
    unsigned long               elf_addr;
    unsigned short	        elf_mark : 1,
                                elf_loader : 1;
};

#ifdef __ELF__

#define ELF_INFO_DEBUG_HEADER   0x0001
#define ELF_INFO_MODULE         0x0002

struct elf_info
{
    unsigned                    flags;          /* IN  one (or several) of the ELF_INFO constants */
    unsigned long               dbg_hdr_addr;   /* OUT address of debug header (if ELF_INFO_DEBUG_HEADER is set) */
    struct module*              module;         /* OUT loaded module (if ELF_INFO_MODULE is set) */
};

struct symtab_elt
{
    struct hash_table_elt       ht_elt;
    const Elf32_Sym*            symp;
    const char*                 filename;
    unsigned                    used;
};

struct thunk_area
{
    const char*                 symname;
    THUNK_ORDINAL               ordinal;
    unsigned long               rva_start;
    unsigned long               rva_end;
};

/******************************************************************
 *		elf_hash_symtab
 *
 * creating an internal hash table to ease use ELF symtab information lookup
 */
static void elf_hash_symtab(const struct module* module, struct pool* pool, 
                            struct hash_table* ht_symtab, const char* map_addr,
                            const Elf32_Shdr* symtab, const Elf32_Shdr* strtab,
                            unsigned num_areas, struct thunk_area* thunks)
{
    int		                i, j, nsym;
    const char*                 strp;
    const char*                 symname;
    const char*                 filename = NULL;
    const char*                 ptr;
    const Elf32_Sym*            symp;
    struct symtab_elt*          ste;

    symp = (const Elf32_Sym*)(map_addr + symtab->sh_offset);
    nsym = symtab->sh_size / sizeof(*symp);
    strp = (const char*)(map_addr + strtab->sh_offset);

    for (j = 0; j < num_areas; j++)
        thunks[j].rva_start = thunks[j].rva_end = 0;

    for (i = 0; i < nsym; i++, symp++)
    {
        /* Ignore certain types of entries which really aren't of that much
         * interest.
         */
        if (ELF32_ST_TYPE(symp->st_info) == STT_SECTION || symp->st_shndx == SHN_UNDEF)
        {
            continue;
        }

        symname = strp + symp->st_name;

        if (ELF32_ST_TYPE(symp->st_info) == STT_FILE)
        {
            filename = symname;
            continue;
        }
        for (j = 0; j < num_areas; j++)
        {
            if (!strcmp(symname, thunks[j].symname))
            {
                thunks[j].rva_start = symp->st_value;
                thunks[j].rva_end   = symp->st_value + symp->st_size;
                break;
            }
        }
        if (j < num_areas) continue;

        /* FIXME: we don't need to handle them (GCC internals)
         * Moreover, they screw up our symbol lookup :-/
         */
        if (symname[0] == '.' && symname[1] == 'L' && isdigit(symname[2]))
            continue;

        ste = pool_alloc(pool, sizeof(*ste));
        /* GCC seems to emit, in some cases, a .<digit>+ suffix.
         * This is used for static variable inside functions, so
         * that we can have several such variables with same name in
         * the same compilation unit
         * We simply ignore that suffix when present (we also get rid
         * of it in stabs parsing)
         */
        ptr = symname + strlen(symname) - 1;
        ste->ht_elt.name = symname;
        if (isdigit(*ptr))
        {
            while (*ptr >= '0' && *ptr <= '9' && ptr >= symname) ptr--;
            if (ptr > symname && *ptr == '.')
            {
                char* n = pool_alloc(pool, ptr - symname + 1);
                memcpy(n, symname, ptr - symname + 1);
                n[ptr - symname] = '\0';
                ste->ht_elt.name = n;
            }
        }
        ste->symp        = symp;
        ste->filename    = filename;
        ste->used        = 0;
        hash_table_add(ht_symtab, &ste->ht_elt);
    }
}

/******************************************************************
 *		elf_lookup_symtab
 *
 * lookup a symbol by name in our internal hash table for the symtab
 */
static const Elf32_Sym* elf_lookup_symtab(const struct module* module,        
                                          const struct hash_table* ht_symtab,
                                          const char* name, struct symt* compiland)
{
    struct symtab_elt*          weak_result = NULL; /* without compiland name */
    struct symtab_elt*          result = NULL;
    struct hash_table_iter      hti;
    struct symtab_elt*          ste;
    const char*                 compiland_name;
    const char*                 compiland_basename;
    const char*                 base;

    /* we need weak match up (at least) when symbols of same name, 
     * defined several times in different compilation units,
     * are merged in a single one (hence a different filename for c.u.)
     */
    if (compiland)
    {
        compiland_name = source_get(module,
                                    ((struct symt_compiland*)compiland)->source);
        compiland_basename = strrchr(compiland_name, '/');
        if (!compiland_basename++) compiland_basename = compiland_name;
    }
    else compiland_name = compiland_basename = NULL;
    
    hash_table_iter_init(ht_symtab, &hti, name);
    while ((ste = hash_table_iter_up(&hti)))
    {
        if (ste->used || strcmp(ste->ht_elt.name, name)) continue;

        weak_result = ste;
        if ((ste->filename && !compiland_name) || (!ste->filename && compiland_name))
            continue;
        if (ste->filename && compiland_name)
        {
            if (strcmp(ste->filename, compiland_name))
            {
                base = strrchr(ste->filename, '/');
                if (!base++) base = ste->filename;
                if (strcmp(base, compiland_basename)) continue;
            }
        }
        if (result)
        {
            FIXME("Already found symbol %s (%s) in symtab %s @%08x and %s @%08x\n", 
                  name, compiland_name, result->filename, result->symp->st_value,
                  ste->filename, ste->symp->st_value);
        }
        else
        {
            result = ste;
            ste->used = 1;
        }
    }
    if (!result && !(result = weak_result))
    {
        FIXME("Couldn't find symbol %s.%s in symtab\n", 
              module->module.ModuleName, name);
        return NULL;
    }
    return result->symp;
}

/******************************************************************
 *		elf_finish_stabs_info
 *
 * - get any relevant information (address & size) from the bits we got from the
 *   stabs debugging information
 */
static void elf_finish_stabs_info(struct module* module, struct hash_table* symtab)
{
    struct hash_table_iter      hti;
    void*                       ptr;
    struct symt_ht*             sym;
    const Elf32_Sym*            symp;

    hash_table_iter_init(&module->ht_symbols, &hti, NULL);
    while ((ptr = hash_table_iter_up(&hti)))
    {
        sym = GET_ENTRY(ptr, struct symt_ht, hash_elt);
        switch (sym->symt.tag)
        {
        case SymTagFunction:
            if (((struct symt_function*)sym)->address != module->elf_info->elf_addr &&
                ((struct symt_function*)sym)->size)
            {
                break;
            }
            symp = elf_lookup_symtab(module, symtab, sym->hash_elt.name, 
                                     ((struct symt_function*)sym)->container);
            if (symp)
            {
                ((struct symt_function*)sym)->address = module->elf_info->elf_addr +
                                                        symp->st_value;
                ((struct symt_function*)sym)->size    = symp->st_size;
            } else FIXME("Couldn't find %s\n", sym->hash_elt.name);